1. Field of the Invention
The present invention relates to an audio signal processing apparatus suitable for use in a stereophonic apparatus called a system stereo in which a plurality of audio appliances are used in combination.
2. Description of the Related Art
In the art, a stereophonic apparatus called a system stereo in which used in combination are a plurality of audio appliances has been on market in various types.
FIG. 1 shows an example of this kind of stereophonic apparatus, in which each of the audio appliances is connected to an amplifier apparatus 50. In detail, a compact disk reproducing apparatus 61 which reproduces a compact disk (CD) on which a digital audio signal is recorded, a tuner 62 receiving an FM broadcast, an AM broadcast and so on, a disk recording and reproducing apparatus 63 which records and reproduces an audio signal by using a magneto optical disk (or optical disk) such as a minidisk (MD) or the like, and a tape recording and reproducing apparatus 64 which records and reproduces an audio signal by using a tape cassette are connected to the amplifier apparatus 50. An audio signal, which is selected by a function change-over switch provided in the amplifier apparatus 50 from the audio signals which are supplied from the respective audio appliances 61, 62, 63 and 64 to the amplifier apparatus 50, is subjected to a predetermined processing (amplification processing in a power amplifier, various signal processing in a DSP and so on) and the audio signal thus processed is supplied to left and right speaker units 65L and 65R connected to the amplifier apparatus 50 and then acoustic sounds are produced therefrom. The audio signal selected by the function change-over switch is also supplied to the apparatuses 63 and 64 capable of recording the audio signal, and a desired audio signal can be recorded by the apparatus 63 or 64.
In the system stereophonic apparatus connected as mentioned above, it is necessary to connect the respective audio appliances 61 through 64 to the amplifier apparatus 50 by using a number of audio signal lines.
FIG. 2 shows an example of the arrangement of a connection terminal portion on the rear surface of the amplifier apparatus 50 shown in FIG. 1. As shown in FIG. 2, there are provided an input terminal 51 to be connected with the compact disk reproducing apparatus 61, an input terminal 52 to be connected with the tuner 62, an input/output terminal 53 to be connected with the disk recording and reproducing apparatus 63, an input/output terminal 54 to be connected with the tape recording and reproducing apparatus 64, and a speaker terminal 55 to be connected with the speaker units 65L and 65R. In this case, the input terminals 51 and 52 are terminals inputted with left and right audio signals, respectively, and each of which is formed of two jacks, while the input/output terminals 53 and 54 are terminals inputted with the left and right audio signals and terminals outputting the same and each of which is formed of four jacks.
As set forth above, on the rear surface of the amplifier apparatus 50, there are arranged a number of connection terminal units, and the respective audio appliances are connected to the amplifier apparatus in such a manner that a plug, which is called a pin plug provided on a tip end of each connection cord connected to each audio appliance, is inserted into each predetermined jack of the amplifier apparatus for connection. The connection work, however, requires much time and further easily permit erroneous connection. In other words, the input and output terminals of the audio signal are formed of jacks that are the same in shape and, as shown in FIG. 2, a name or the like of the appliance to be connected is indicated near each terminal. However, upon carrying out an actual connecting work, since a number of jacks are the same in shape and also located close to one another, the connection is mistaken frequently.
In view of the problem mentioned above, it is an object of the present invention to provide an audio signal processing apparatus by which the connection work of a system stereophonic apparatus can be carried out easily with no complexity.
According to the present invention, there is provided an audio signal processing apparatus which is provided with a plurality of terminal units each having at least an audio signal input contact piece and a control signal contact piece, and a control means for judging the kind of an audio appliance connected to each terminal unit on the basis of a control signal obtained at the terminal unit and for making a function selection means select, when a function change-over command to select any of the audio appliances is issued, a terminal unit to which is connected the appliance of kind thus discriminated.
According to the present invention, when a function change-over command to change over an audio appliance is issued by a key operation or the like, the terminal unit connected with the appliance indicated by that command is judged by the control means, and the corresponding terminal unit is selected by the function selection means. Therefore, even when a plurality of audio appliances are connected to any ones of a plurality of terminal units prepared in any order, the connected audio appliance can be selected correctly.